1. Field of the Invention
The present invention relates to the field of antennas.
More precisely still the present invention relates to the field of antennas operating with regard to a particular mode comprising:
a first electrically conductive surface, generally dubbed a "capacitive roof", PA1 a second electrically conductive surface forming a ground plane, parallel to the first surface, PA1 a first electrically conductive feed wire or strip which links a first terminal of a generator/receiver to the first surface and a second feed wire or strip which links a second terminal of the generator/receiver to the second surface, and PA1 at least one electrically conductive wire or strip which links the two aforesaid surfaces.
2. Description of the Related Art
Examples of such antennas are described, for example in the documents FR-A-2 668 859 and EP-A-667 984.
Thus, the document FR-A-2 668 859 has described an antenna of the aforesaid type comprising a single wire or strip linking the two surfaces, which wire or strip is arranged so as to be traversed by a current at the working frequency and so as to be coupled by inductive coupling to the feed wire or strip linking the generator to the first surface. It has been shown that this antenna generates, under certain conditions of layout of the elements, a radiation of monopole type, that is to say comprising an axisymmetric lobe, with maximum radiation parallel to the ground plane and zero radiation perpendicular to the antenna, linear polarization with electric field in a plane perpendicular to the antenna and near hemispherical coverage except on the axis.
The document EP-A-667 984 describes a variant of this antenna comprising several parallel wires or strips linking the two surfaces. This arrangement makes it possible in particular to facilitate the matching of the antenna to the generator.
The antennas of the aforesaid type have already rendered great service.